Electric clock



Jan. 30, 1934. G. F. HARTER 1,945,272

ELECTRIC CLOCK Filed April 15, 1932 In ven ton 660236 I? Harte);

W ,Mm Q/W Attj/S Patented Jan. 30, 1934 PATENT OFFICE 7 ELECTRIC CLOCK George F. Barter, Springfield, Mass., assignor to Standard Electric Time Company, Springfield. Mass., a corporation of Connecticut Application April 15, 1932. Serial No. 605,470

9 Claims.

This invention relates to electric clock systems of the type wherein a plurality of secondary clocks are operated by impulses sent outby a master clock and are periodically brought into synchronism therewith.

Objects of the present invention are to provide a secondary clock of the aforesaid type which is of simple design and inexpensive to manufacture, which is reliable and efficient in operation, and which is a marked improvement over similar types heretofore used. Further objects relate to the operation and construction of the corrective mechanism and will be apparent from a consider ation of the following description and accompanying drawing, wherein:

Fig. 1 is a circuit diagram including a master clock and secondary clocks;

Fig. 2 is a rear elevation of the operating mechanism of a secondary clock;

Fig. 3 is a view of a secondary clock from the line 3-3 of Fig. 2;

Fig. 4 is a section on the line 4-4 of Fig. 3;

Fig. 5 is a view similar to Fig. 4 showing the driving mechanism just after being released from locked position; and

Fig. 6 is an enlarged fragmentary elevation, partly in section, of the locking mechanism.

The particular embodiment of the invention chosen for the purpose of illustration comprises secondary clocks each having driving magnets D for advancing the clock in response to normal and fast impulses sent out from the central station or master clock, and magnets R for releasing the locking mechanism (hereinafter to be fully described) in response to periodic impulses which are also sent out from the master clock.

The master clock may be of any well known' type having the usual time train including a second arbor driven at the rate of one revolution per minute, a minute arbor rotating at one revolution per hour, and a verge mechanism. Fixed to the second arbor is a cam 5 which controls the opening and closing of contacts 6 to send out an impulse every minute over line N to the driving magnets D. Cams 8 and 9 are mounted on the minute arbor and respectively control the operation of contacts 10 and 11 which close once each hour. The fast impulms are sent out by means of the verge mechanism which closes contacts 13 at each oscillation of the pendulum and thus causes a series of rapid impulses to be sent out over line N to the driving magnets D once during each hour to accelerate all slow clocks.

The arrangements of the parts are such that contacts 10 and 11 are normally open and are closed only for short intervals between the 59th and th minutes, contacts 11 closing just after the 59th minute impulse has been sent out and opening about thirty seconds later, and contacts 10 closing momentarily just after contacts 11 0 open to send out a single impulse over line S to the release magnets R. The line C connects each of the magnets D and R with the master clock and source of current B and thus provides a common return. I

As shown in Figs. 2 to 5 inclusive, each secondary clock comprises two ratchet wheels 21 and 22 mounted on the same shaft and having their teeth facing in opposite circumferential directions, the ratchet wheel 21 serving to drive the clock train and the ratchet wheel 22 serving to prevent overthrow. The ratchet wheel 21 is driven by pawl 23 pivotally secured to lever 24 which is pivoted at 25. The lever 24 carries an armature 26 which is attracted by the driving magnet D, a pin 2'7 which engages the teeth of the ratchet wheel 22 to prevent overthrow, and a laterally projecting locking pin 28 adjacent to the driving pawl 23. The forward or clock advancing movement of the pawl is effected either by gravity or preferably by a spring (not shown) which normally holds the lever in forward position as shown in Fig. 2. A pawl 29 pivotally secured to bracket 30 engages the ratchet wheel 21 to prevent retrograde movement of the clock train while the pawl 23 is retracted.

Pivotally mounted on the yoke 35 is a plate 36, the upper portion of which carries a laterally projecting stop 37 which extends forwardly in juxtaposition to the rearwardly projecting locking pin 28 carried by lever 24. Preferably the plate is so shaped that its center of gravity lies to the right of its pivot 38 (as viewed in Figs. 2 and 3) and normally is held by gravity in the posittion shown by the full lines in Figs. 2 and 4 (and by the dotted lines in Fig. 5), its tendency to rotate further in a clockwise direction (Fig. 2) being limited by the lug 39 which projects rearwardly from its lower end and engages the yoke 35. As shown in Figs. 4. 5 and 6, the stop 37 is preferably angularshaped to provide a depending portion which engages pin 28 and prevents the plate 36 from being swung too far in a clockwise direction, as viewed in Figs. 4 and 5.

The plate 36 carries a forwardly projecting pin 42 and a bracket 43 which is provided with openings in its free end 44 to receive the bifurcate end of a latch member designated generally by the numeral 45 (Fig. 6). As shown in Fig. 6, the end of the. latch 45 loosely fits in the openings in the bracket 43 and has a pivotal movement about the end 44 of the bracket, the pin 42 serving to limit this movement. The latch is normally held in yielding engagement with the pin 42 by a small coil spring 48 carried by one of the prongs of its bii'urcate end, the opposite end of the latch terminating in a downward and outwardly extending linger 46. Adjacent to its bight, the latch carries a forwardly projecting stop 50 which, as shown in Fig. 4, is normally disposed in the path of a pin or abutment 52 carried by the ratchet wheel 22.

As a clock train is advanced in response to impulses transmitted to the driving magnet D, it is apparent that at a predetermined point in its cyclic movement the pin 52 will engage the stop 50 and cause the plate 36 to swing in a clockwise direction from its normal position as shown in the full lines in Fig. 4 to locking position with the stop 37 in overhanging engagement with the pin 28 as shown by the dotted lines in Fig. 4 and the full lines in Fig. 5. As thus positioned, the stop 37 positively locks the lever 24 in fixed position and prevents further oscillation thereof, and the stop 50 being in engagement with the pin 52 not only holds the ratchet wheels against further advancement, but also holds the plate 36 in looking position. With the driving mechanism thus locked the clock remains unresponsive to further impulses through the driving magnet D until the latch 45 is released to allow the plate 36 to swing back to normal position.

The releasing mechanism comprises a release lever 55 pivoted at 56 to the yoke 35, and an armature 5'7 carried thereby and disposed in cooperative relation to the magnet R. The lever is normally held in retracted position preferably by a spring (not shown) and is adapted to swing in a clockwise direction (Figs. 4 and 5) so that its arm 58 engages the finger 46. Upon the receipt of an impulse from the master clock the magnet R attracts the armature and swings the latch 45 upwardly so that the stop 50 clears pin 52 as shown in the full lines in Fig. 5 and thus permits the plate 36 to swing from looking position back to normal position as shown by the dotted lines in Fig. 5. Under the action of the spring 48 the latch 45 swings downwardly and the stop 50 returns to its normal position in the path oi! pin 52 to engage the same during the next succeeding cycle. The actuating lever 24 is now free to oscillate and the ratchet wheels may be stepped ahead in the usual manner.

The locking pin 52 on each of the secondary clocks is so arranged relative to the hands of the clock that the actuating lever 24 and the driving ratchet are locked when the minute hand indicates the period during which the clocks are brought into synchronism with the master clock, which is preferably the 59th minute. Thus, all clocks are automatically stopped and locked when their minute hands indicate one minute before, the hour, and can not be advanced until the actuation of the releasing mechanism is effected by the periodic impulse sent out from the master clock to magnet R.

The operation of the system shown in Fig. 1 is as follows: The secondary clocks are connected in multiple with the master clock by lines N-S-C and are advanced each minute by the normal impulses transmitted over the lines N-C by the closing of contacts 6. If for any reason any of the secondary clocks become fast, when they reach the 59th minute as indicated by their minute hands, they will be automatically stopped and will remain unresponsive to further impulses received by driving magnets D. All clocks which are on time will be automatically stopped, upon receipt oi! the 59th impulse and will also remain unresponsive to further impulses to the driving magnet. Just after the 59th impulse, earn 9 closes contact 11 for a period of about 20 to 30 seconds and thus effects the transmission oi a series 0! rapid impulses over lines N and C to the driving magnets D. Should any of the clocks be slow at the 59th minute, they will be accelerated by the'rapid impulses until they are brought into synchronism with the master clock with-their minute hands indicating one minute before the hour, at which time their locking mechanisms are brought into action to restrain further response to the impulses. All secondary clocks are thus brought into synchronism with the master clock and indicate one minute before the hour.

A few seconds after cam 9 opens contacts 11, which opening may occur from 30 to 50 seconds after the 59th impulse, cam 8 closes contacts 10 momentarily to effect the transmission of a single impulse over lines S--C to the magnets R which,

as previously explained, eiiects the actuation of Y the release mechanism and restores each secondary to the control of the normal impulses to magnet D. On the 60th minute or the even hour, the usual 60th minute impulse is transmitted to advance all clocks to the hour position.

It should be understood that the present disclosure is for the purpose of illustration only and that various changes in shape, proportion, and arrangement of parts as well as the substitution of equivalent elements for those herein shown and described may be made without departing from the spirit and scope of this invention as set forth in the appended claims.

I claim:

1. A secondary clock having an oscillating driving mechanism for advancing the clock train step-by-step in response to impulses from a master clock, and corrective means for automatically rendering said driving means ineiiective at predetermined intervals, said corrective means comprising a movable stop member engageable with said driving mechanism to obstruct its oscillating movement, a latch member pivotally connected to said stop and adapted to hold the same in obstructing position, and an abutment movable in an orbital path with the clock train and engageable with said latch at a predetermined point in its path to move said stop into obstructing position.

2. A secondary clock having an oscillating driving mechanism for advancing the clock train stepbystep in response to impulses from a master clock, and corrective means for automatically rendering said driving means inefiective at predetermined intervals, said corrective means comprising a stop movable from a normal position to a position in which it obstructs the oscillating movement to said driving mechanism, a latch pivotally connected to said stop, and means engageable with said latch at a predetermined point in the cyclic movement of the clock train for moving said stop from normal to locking position, thereby to restrain further advance oi. said clock.

3. A secondary clock having an oscillating driving mechanism for advancing the clock train step-by-step in response to impulses from a master clock, corrective means for automatically rendering said driving means ineflective at predetermined intervals, said corrective means comlid prising a stop movable from a normal position to a position in which it obstructs the oscillating movement of said driving mechanism, a latch pivotally connected to said stop, and means engageable with said latch at a predetermined point in the cyclic movement of the clock train for moving said stop from normal to a locking position, thereby to restrain further advance of said clock, and means engageable with said latch to move said stop from looking position to normal position, thereby to release said driving mechanism.

4. A secondary clock having a driving mechanism including a ratchet wheel and pawl for advancing the clock train step-by-step in response to driving impulses from a master clock, corrective means for rendering said driving means ineffective at predetermined intervals, said corrective means comprising a movable stop member engageable with said driving mechanism to lock said pawl against retraction, a latch member pivotally connected to said stop, and means engageable with said latch at a predetermined point in the cyclic movement of the clock train for moving said stop to locking position, and means responsive to other impulses from the master clock and engageable with said latch for removing said stop from looking position.

5. A secondary clock having a driving mechanism including a ratchet wheel and pawl for advancing the clock train step-by-step in response to driving impulses from a master clock, corrective means for rendering said driving means ineffective periodically in accordance with the chronological condition of said clock, said corrective means comprising a stop movable from a normal position to a locking position in which it holds said pawl against retraction, a latch pivotally connected to said stop and adapted to retain the same in locking position, and means engageable with said latch at a predetermined point in the cyclic movement of said clock train for moving said stop from normal to locking position, and means for releasing said latch to cause .said stop to return to normal position.

6. A secondary clock comprising a driving mechanism including a ratchet wheel and pawl for advancing the clock train step-by-step in response to driving impulses from a master clock, corrective means for rendering said driving means ineffective periodically in accordance with the chronological condition of said clock, said corrective means comprising a stop movable from a normal position to a locking position in which it holds said pawl against retraction. an abutment movable in an orbital path with the clock train, a latch pivoted to said stop member and normally disposed in the path of said abutment, said abutment being engageable with said latch at a predetermined point in the cyclic movement of the clock train to move said stop from normal to locking position, said abutment cooperating with said latch to hold the stop in looking position, and means for releasing said latch to cause the stop to return to normal position, said releasing means automatically effecting the-repositioning of said latch to engage said abutment durtrain, a latch pivoted to said stop member and' movable from a normal position in the path of said abutment to a position outside of said path, said abutment being engageable with said latch at a predetermined point in the cyclic movement of the clock train to move said stop from normal to locking position, said abutment and latch cooperating to retain said stop in looking position, means operable in response to other impulses from the master clock for releasing said latch, and means operative upon release of said latch for effecting the repositioning of said latch and stop to their normal positions wherein they become operative during the next successive cycle of the clock train.

8'. A synchronized clock system comprising a master clock and a secondary clock of the type having an oscillatingdrivlng mechanism for advancing the clock train step-by-step, means in the master clock for transmitting driving im-- pulses to the secondary clock, and corrective means in the secondary clock for eifecting synchronism between the master clock and the secondary clock periodically in accordance with the chronological condition of said clock, said corrective means including a stop for obstructing the oscillating movement of the driving mechanism, a latch pivoted to said stop for holding the same in obstructing position, and means constructed and arranged to efiect obstructing action of said stop automatically at a predetermined point in the cyclic movement of the clock train.

9. A synchronized clock system comprising a master clock and a secondary clock of the type having an oscillating driving mechanism for advancing the clock train step by step, means in the master clock for transmitting driving impulses to the secondary clock, and corrective means in the secondary clock for effecting synchronism between the master clock and the secondary clock periodically in accordance with the chronological condition of said clock, said corrective means including a stop movable from a normal position to a locking position in which it obstructs the oscillating movement of said driving mechanism, a latch pivotally secured to said stop and adapted to hold the same in looking position, means constructed and arranged to effect locking action of said stop automatically at a predetermined point in the cyclic movement of the clock train, means for releasing said latch, and means operative upon release of said latch to restore said stop to normal position.

GEORGE F. HARTER. 

